Cut 100g of the watermelon in small cubes 1x1x1 cm. Blend rest into juice (40 ml).

Melt butter in electric oven at 5~600W for 40~50 seconds or until it is completely melted. Keep warm.
Pre-heat oven to 180 degrees Celsius.

Mix sugar and eggs together. Warm sufficiently until it gets to your “skin temperature”.
Beat up at High Medium speed until it forms a bubbly but fine paste. Continue to beat at low speed for 3 more minutes.

Add rice flour and delicately with a spatula.

Mix in melted butter and watermelon juice delicately.

Pour in molds.

Place a watermelon cube on top and bake for 20 minutes at 180 degrees Celsius.